1. Field of the Invention
The invention relates generally to the field of television program ratings measurement and more particularly to methods for identifying the composition of the viewing audience watching TV programs and commercials.
2. Brief Description of the Prior Art
Conventional methods of monitoring tv audiences include meters attached to the tv set to minotor the channel tuning of the set. This has proved to be inadequate in a era where advertisers want to know precisely who is watching tv and when. Thus passive tv audience meters have been proposed. These meters include push-buttons an audience member must push when he enters or leaves the room. Other methods include, and the following does not constitute prior art to the applicant, headphones an audience member must wear to hear the audio. These headphones are activated when a member of the audience puts them on and deactivated when he takes them off.
One method of determining the pressure of active headphones is to poll them. The receipt of an acknowledgement indicates a headphone present on the head of a viewer. Headphone audio is enabled in response to the receipt of a poll if electrical means in the headphone indicates activation of the acknowledgement mechanism. Guest headphones are included in the poll list by a guest logging information about himself into the meter and identifying the guest headphone he wishes to use. Viewing is determined to have ceased (and guests headphones removed from the poll list) when a predetermined number of poll acknowledgements are not received.
This polling scheme is not fail safe. Either the headphone response or meter polling receipt mechanisms may fail without the member of the household (whose headphone is always in the poll list and receiving polls) knowing it. Polls are received and audio enabled, but no credit is given for the member's viewing because no acknowledgements are received.
Guest headphones are not adequately handled in that if acknowledgements are not received for a time sufficient for the meter to determine that viewing has ceased, the ID of the guest headphone is taken from the poll list and the guest must reenter his information into the meter in order to reacquire audio. This can be very annoying for the guest (or household member using a guest headphone) taking a short break.